The Department of Biochemistry &Molecular Biology (BMB) and the Department of Chemistry (Chem) at The University of Chicago propose continuation and expansion of an interdisciplinary, predoctoral training program directed at the interface of the chemical and biological sciences. The program emphasizes crosstraining with a synthetic and mechanistic focus. Under the direction of the Principal Investigator in close consultation with a faculty Steering Committee and the co-director/co-principal investigator designated by faculty participants, the program has undergone significant expansion through faculty recruitment and introduction of new courses in interdisciplinary science. Nine faculty members with appointments in BMB, seven in Chem, and one each in the Departments of Pathology and of Neurobiology, Pharmacology, &Physiology form the teaching component of the program. Seven new faculty members have been recruited to the program since its initiation six years ago. Cross-training is achieved by: (1) satisfactory completion of two courses in the department of the other scientific discipline as electives;(2) an elective research rotation under the guidance of a participating faculty member in the other discipline upon initial appointment to the program in the Spring Quarter of the first year of graduate study;(3) coordinated mentoring of student-trainees by the primary research advisor together with a co-advisor of the other department up to the time of the final Ph. D. oral defense;and (4) participation in a series of monthly meetings throughout the academic year designated as "Discussions at the Interface of Chemistry &Biology" to gain acquaintance with theoretical concepts and methods. The broad scope of the interdisciplinary research interests of the faculty, strengthened through collaborative research projects and interactions, ensures a large variety of opportunities for a meaningful cross-training experience. In contrast to the initial, small nucleus of faculty committed to cross-disciplinary research and teaching six years ago, the program presently enjoys broad faculty support and offers a supportive environment for training of students in cutting-edge research at the interface of chemistry and biology. This will be significantly enhanced through relocation of the laboratories of all participating BMB and Chem faculty into the new Institute for Interdivisional Research over the next 10-month period.